The invention relates to a method of accelerating a projectile or a controlled missile to hypervelocity speeds (2 km/sec. to 12 km/sec.) utilizing external propulsion obtained by continuous detonation waves generated on a suitably designed planar-winged or axi-symmetric vehicle based on the "Waverider" concept. It relates more particularily to a method of propelling a projectile or a missile at the required velocity through a space filled with a pressurized fuel-oxidizer gas mixture, causing detonation and combustion of the gas mixture on the rear parts of the vehicle and thus obtaining forward thrust, without the necessity of fuel to be carried by the vehicle itself.
The concept of external propulsion based on the "Ram Jet" cycle, with combustion or detonation processes, was already proposed in the early 1960's for various hypersonic aircraft designs. However, it was found not to be practical because of the long path required for reasonable mixing of the injected fuel with the external airstream.
The principle of the "Ram Jet" cycle is as follows: air flowing into the ramjet engine is pressurized and decelerated by shock waves generated in the supersonic diffuser section. This deceleration can be done by utilizing a normal shock wave to subsonic velocity which is then directed to the combustion section where subsonic combustion of the injected fuel is accomplished. The high temperature-pressure combustion products are then expanded in a convergent-divergent nozzle to high velocity jet which imparts forward thrust on the complete engine. A more efficient cycle can be obtained if the ram deceleration is done by oblique shock waves to lower supersonic velocities, and fuel is injected and combustion is accomplished at supersonic speeds. The combustion products are then accelerated by an expanding nozzle to obtain forward thrust. Since there are difficulties in stabilizing supersonic combustion, there exist experimental programs to stabilize oblique detonation waves to produce the high temperature/high pressure combustion products.
A direct application of the Ram Jet process to accelerate projectiles to high velocities was developed by Prof. A. Hertzberg and his associates at the University of Washington, Seattle, Wash. in their "Ram Accelerator". Herein a properly shaped projectile is fired, by a gun or by other means, into and along a strong gun barrel filled with pressurized fuel-oxidizer gas mixture. The configuration of the projectile and the barrel correspond to the design of a "Ramjet" engine wherein the projectile acts as the centerpart on which the forward thrust is affected, while the gun barrel acts as the engine cowling. The drawback of this process lies in the high pressures which are inherently being generated on the barrel walls, and which increase considerably as the speed of the projectile is increased. This is due to the fact that the initial gas mixture pressure must be reasonably high, about 100-200 bars, in order to obtain the high thrust for the acceleration of the projectile; and final pressure on the barrel wall may be from 100 to 1000 times this value due to the shock wave structure required in order to obtain the Ram cycle which is the basic cycle of the "Ram Accelerator". Therefore the "Ram Accelerator" requires a very thick and heavy barrel of an extremely high weight at projectile velocities above 5-6 km/sec.
In order to alleviate this drawback it is the main object of the present invention to provide a method for propelling a projectile that utilizes the external propulsion concept instead of the ramjet concept to accelerate projectiles to hypervelocities. In this way the high pressures due to the shock and detonation waves are attached to the vehicle and the pressure rise due to the waves is lower when these arrive at the tube walls, which are remote from the projectile.
Since by this method a relatively large vehicle can be propelled at hypervelocity, it is another object of this invention to provide such a vehicle with controls--aerodynamic or propulsive--and guidance systems for locating a target and for directing and maneuvering the vehicle towards it.
It is still another object to provide the vehicle with additional propulsive systems such as rocket engines that will be initiated while the vehicle is in free flight and so to further accelerate the vehicle to still higher velocities beyond those obtained by the present method and device.
It is still another object to position a complete propelling system on the ground, in a fixed base or on a ground-transportable vehicle (armored or not).
It is still another object to provide means for firing a projectile from a device mounted on an aircraft or on a space vehicle.
It is another object to provide such a system, adapted to propel vehicles to velocities beyond the escape velocities from the earth gravitational force, with or without the assistance of rockets.